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some cleaning on signed opcode parameters

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This commit is contained in:
Roberto Ierusalimschy
2017-12-15 16:53:48 -02:00
parent 4b6928e7f5
commit f8c1c1469a
3 changed files with 50 additions and 27 deletions
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44
lcode.c
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@@ -1,5 +1,5 @@
/*
** $Id: lcode.c,v 2.143 2017/12/13 18:32:09 roberto Exp roberto $
** $Id: lcode.c,v 2.144 2017/12/14 14:24:02 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -108,7 +108,7 @@ static void fixjump (FuncState *fs, int pc, int dest) {
Instruction *jmp = &fs->f->code[pc];
int offset = dest - (pc + 1);
lua_assert(dest != NO_JUMP);
if (abs(offset) > MAXARG_sJ)
if (!(-OFFSET_sJ <= offset && offset <= MAXARG_sJ - OFFSET_sJ))
luaX_syntaxerror(fs->ls, "control structure too long");
lua_assert(GET_OPCODE(*jmp) == OP_JMP);
SETARG_sJ(*jmp, offset);
@@ -360,7 +360,7 @@ int luaK_codeABCk (FuncState *fs, OpCode o, int a, int b, int c, int k) {
}
#define codeABsC(fs,o,a,b,c,k) luaK_codeABCk(fs,o,a,b,((c) + MAXARG_sC),k)
#define codeABsC(fs,o,a,b,c,k) luaK_codeABCk(fs,o,a,b,((c) + OFFSET_sC),k)
@@ -378,7 +378,7 @@ int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
** Format and emit an 'iAsBx' instruction.
*/
int luaK_codeAsBx (FuncState *fs, OpCode o, int a, int bc) {
unsigned int b = bc + MAXARG_sBx;
unsigned int b = bc + OFFSET_sBx;
lua_assert(getOpMode(o) == iAsBx);
lua_assert(a <= MAXARG_A && b <= MAXARG_Bx);
return luaK_code(fs, CREATE_ABx(o, a, b));
@@ -389,7 +389,7 @@ int luaK_codeAsBx (FuncState *fs, OpCode o, int a, int bc) {
** Format and emit an 'isJ' instruction.
*/
static int codesJ (FuncState *fs, OpCode o, int sj, int k) {
unsigned int j = sj + MAXARG_sJ;
unsigned int j = sj + OFFSET_sJ;
lua_assert(getOpMode(o) == isJ);
lua_assert(j <= MAXARG_sJ && (k & ~1) == 0);
return luaK_code(fs, CREATE_sJ(o, j, k));
@@ -582,8 +582,26 @@ static int nilK (FuncState *fs) {
}
/*
** Check whether 'i' can be stored in an 'sC' operand.
** Equivalent to (0 <= i + OFFSET_sC && i + OFFSET_sC <= MAXARG_C)
** but without risk of overflows in the addition.
*/
static int fitsC (lua_Integer i) {
return (-OFFSET_sC <= i && i <= MAXARG_C - OFFSET_sC);
}
/*
** Check whether 'i' can be stored in an 'sBx' operand.
*/
static int fitsBx (lua_Integer i) {
return (-OFFSET_sBx <= i && i <= MAXARG_Bx - OFFSET_sBx);
}
void luaK_int (FuncState *fs, int reg, lua_Integer i) {
if (l_castS2U(i) + MAXARG_sBx <= l_castS2U(MAXARG_Bx))
if (fitsBx(i))
luaK_codeAsBx(fs, OP_LOADI, reg, cast_int(i));
else
luaK_codek(fs, reg, luaK_intK(fs, i));
@@ -593,8 +611,7 @@ void luaK_int (FuncState *fs, int reg, lua_Integer i) {
static int floatI (lua_Number f, lua_Integer *fi) {
TValue v;
setfltvalue(&v, f);
return (luaV_flttointeger(&v, fi, 0) &&
l_castS2U(*fi) + MAXARG_sBx <= l_castS2U(MAXARG_Bx));
return (luaV_flttointeger(&v, fi, 0) && fitsBx(*fi));
}
@@ -1089,8 +1106,7 @@ static int isCint (expdesc *e) {
** proper range to fit in register sC
*/
static int isSCint (expdesc *e) {
return (e->k == VKINT && !hasjumps(e) &&
l_castS2U(e->u.ival + MAXARG_sC) <= l_castS2U(MAXARG_C));
return (e->k == VKINT && !hasjumps(e) && fitsC(e->u.ival));
}
@@ -1103,8 +1119,12 @@ static int isSCnumber (expdesc *e, lua_Integer *i) {
*i = e->u.ival;
else if (!(e->k == VKFLT && floatI(e->u.nval, i)))
return 0; /* not a number */
*i += MAXARG_sC;
return (!hasjumps(e) && l_castS2U(*i) <= l_castS2U(MAXARG_C));
if (!hasjumps(e) && fitsC(*i)) {
*i += OFFSET_sC;
return 1;
}
else
return 0;
}